362 THE HISTORY OF CREATION. 
by a strait, but they have now for the most part sunk 
below the level of the sea. Wallace, solely on the ground of 
his accurate chorological observations, has been able in the 
most acute manner to determine the position of this former 
strait, the south end of which passes between Balij and 
Lombok. 
Thus, ever since liquid water existed on the earth, the 
boundaries of water and land have eternally changed, and 
we may assert that the outlines of continents and islands 
have never remained for an hour, nay, even for a minute, 
exactly the same. For the waves eternally and perpetually 
break on the edge of the coast, and whatever the land in 
these places loses in extent, it gains in other places by the 
accumulation of mud, which condenses into solid stone and 
again rises above the level of the sea as new land. Nothing 
can be more erroneous than the idea of a firm and 
unchangeable outline of our continents, such as is im- 
pressed upon us in early youth by defective lessons on 
geography, which are devoid of a geological basis. 
I need hardly draw attention to the fact that these 
geological changes of the earth’s surface have ever been ex- 
ceedingly important to the migrations of organisms, and 
consequently to their Chorology. From them we learn to 
understand how it is that the same or nearly related species of 
animals and plants can occur on different islands, although 
they could not have passed through the water separating 
them, and how other species living in fresh water can inhabit 
different enclosed water-basins, although they could not have 
crossed the land lying between them. These islands were 
formerly mountain peaks of a connected continent, and 
these lakes were once directly connected with one another. 
Ee ee Oe 
